The present invention relates to packaging and packaging materials, and more particularly to paper or paperboard substrates which include a moisture vapor barrier layer that also has good resistance to oxygen permeation. Examples of such barrier materials are disclosed in the article "High Barrier Polymers", by A. L. Blackwell, published in the TAPPI Notes of the 1986 TAPPI Coextrusion Seminar. It is also desirable in the manufacture of such products that the barrier materials be applied to the paper or paperboard at the same time that the products are printed and converted into packages as disclosed for example in U.S. Pat. No. 5,418,008. In order to satisfy both of these purposes, resins of polyvinylidene chloride (PVDC) in the form of aqueous coatings, which can be applied on a printing press, have been found to be successful.
Examples of prior art PVDC coated papers are illustrated, for example, in U.S. Pat. No. 2,392,972, which discloses kraft paper having a layer of a vinylidene chloride copolymer applied over an intermediate coating of a vinyl chloride-acetate copolymer to achieve good adhesion to the paper; U.S. Pat. No. 3,231,411, which discloses a layer of PVDC applied over a primer layer to a substrate comprising paper with a coating of polyethylene, where the primer layer acts as a binder between the polyethylene layer and the PVDC layer; U.S. Pat. No. 3,476,587, which discloses a substrate including two coatings of vinylidene chloride copolymers, one being hard and brittle, and the other being supple; U.S. Pat. No. 3,579,371, which discloses a packaging structure comprising a cellulosic substrate carrying an intermediate coating of PVDC resin and a top coating consisting of a blend of an alkyd resin and an amine-aldehyde resin; U.S. Pat. No. 3,707,393, which discloses a sheet material for form-fill packaging having heat seal properties wherein a top coating of PVDC is applied over an undercoating of a mixture of two copolymers consisting of (A) a copolymer of ethylene and a partially neutralized alpha, beta ethylenically unsaturated carboxylic acid, and (B) a copolymer of ethylene and a vinyl alkanoate and from 0 to 10% of an alpha, beta ethylenically unsaturated carboxylic acid; and U.S. Pat. No. 4,300,969, which discloses a packaging laminate consisting of a cardboard web having a layer of heat-sealable thermoplastic material applied to one surface, and three layers of plastic material on the other surface, wherein the middle of the three layers consists of PVDC. Each of the prior art patents described are directed to overcome certain problems inherent with the application of a PVDC resin to a cellulosic substrate, e.g., the difficulty in getting PVDC to adhere to paper or paperboard. However, none of these patents solve the problem addressed by the present invention.